be assumed to be applicable to other areas with the same latitude assuming 
that there are no great climatic differences which could effect the disturb- 
ing weather factors mentioned beyond. Also with suitable corrections, these 
may be applied to localities farther north or farther south, where the twi- 
Light period is of different length. The optimum period in the morning, 
in the vicinity of )6° N. Lat., is from 75 to © minutes before local sun- 
rise; and in the ena ne from 30 to 60 minutes after sunset. 
Table 23. --Time of day of winnowing peak (in minutes 
after sunset or before sunrise) 
Beginning of § End of 
winnowing peak _ | winnowing peak 
7% | 70)5.8) 4 35 
68 S6 17.411 28 
33 | 38 4.8] 5 35 
32 43 16.9/15 33 

Earliest 
Latest 
oN 
Number 
of days 
Length 
Evening 
Manitoulin 
Island 
Sackville, 
N.5. 
Morning — 
Manitoulin 
Island 
Sackville, 
N.B. 
63 
